WBR0769
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Dermatology |
| Prompt | [[Prompt::A 14 year old boy is brought by his mother to the physician's office for pruritic lesions on his skin. The mother informs the physician that the child just recently returned from a picnic and was exposed to poison ivy. On physical examination, the physician notes vesicular bullous lesions with erythema on the lower extremities. The patient's condition is best characterized by a hypersensitivity disorder that resembles which other disease?]] |
| Answer A | AnswerA::Pernicious anemia |
| Answer A Explanation | AnswerAExp::Pernicious anemia is a type II hypersensitivity disorder. |
| Answer B | AnswerB::Multiple sclerosis (MS) |
| Answer B Explanation | AnswerBExp::MS is caused by a type IV hypersensitivity disorder. |
| Answer C | AnswerC::Systemic lupus erythematosus (SLE) |
| Answer C Explanation | AnswerCExp::SLE is caused by a type III hypersensitivity disorder. |
| Answer D | AnswerD::Atopic dermatitis |
| Answer D Explanation | AnswerDExp::Eczema or atopic dermatitis is caused by a type I hypersensitivity disorder. |
| Answer E | AnswerE::Poststreptococcal glomerulonephritis (PSGN) |
| Answer E Explanation | AnswerEExp::PSGN is a caused by a type III hypersensitivity disorder. |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The patient is presenting with contact dermatitis following exposure to poison ivy, a common allergen. Contact dermatitis is caused by a type IV (delayed) hypersensitivity reaction. Similarly, multiple sclerosis is also caused by a type IV hypersensitivity disorder. Other diseases that are also implicated in this type of disorder are: Guillain-Barre syndrome, graft-vs-host disease, and PPD testing for Mycobacterium tuberculosis.
Educational Objective: Contact dermatitis and multiple sclerosis are both caused by a type IV hypersensitivity disorder. |
| Approved | Approved::No |
| Keyword | WBRKeyword::multiple, WBRKeyword::sclerosis, WBRKeyword::type III, WBRKeyword::hypersensitivity, WBRKeyword::disorder, WBRKeyword::type I, WBRKeyword::type II, WBRKeyword::type IV, WBRKeyword::dermatitis, WBRKeyword::contact, WBRKeyword::irritant, WBRKeyword::allergic, WBRKeyword::atopic |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |